Train control system



TRAIN CONTROL SYSTEM Filed Feb. 2, 1931 5 Sheets-Sheet 2 Iuuaniur HZTF'E'EZ EFE S'T Hucld May 23, 1933. A. E. HUDD 1,910,437

TRAIN CONTROL SYSTEM Filed Feb/2, 1931 5 Sheets-Sheet 5 May 23, 1933. A. E. HUDD TRAIN CONTROL SYSTEM Filed Feb. 2, 1931 5 Sheets-Sheet 4 [fair-12w 51m Em Hudd Niay 23, 1933. A.'E. HUDD TRAIN CONTROL SYSTEM Filed Feb. 2, 1931 5 Sheets-Sheet 5 HZTFEEZ EI'Z'LESZ Hudd Patented May 23, 1933 UNITED STATES PATENT OFFICE v ALFRED ERNEST HUDD, OF SURBITON, ENGLAND, ASSIGNOR, BY MESNlE ASSIGNMENTS,

TO ASSOCIATED ELECTRIC LABORATORIES, INC.,

TION OF DELAWARE Application filed February '2, 1931, Serial No.

The-present invention relates to improvements in or relating to train control or cab signalling systems and to track apparatus or locomotive apparatus for use therewith.

Various proposals have been put forward for controlling the application of brakes of a train in accordance with track conditions or of giving signals in the cabin indicative of the track conditions so as to warn the driver in case of his passing a signal at danger.

The object ofthe present invention is to effect adequate control of trains both as regards control of the brakes and control. of cab signals, in a much more economical and cheaper form than has hitherto been considered possible.

The principal difficulty in connection with the problem concerns the arrangement by which apparatus on a locomotive is controlled from the track. The present invention relates more particularly to the system known as the intermittent inductive system in which the flux of magnets located on the track is collected, by magnetic plates sup ported from the locomotive, to effect the operation of an armature located between the plates. Usually such an armature has been influenced to operate contacts in an electrical circuit and, consequently, it has been necessary to provide on the locomotive electrical circuits and electrical power such as batteries to effect control of the train apparatus. It has previously been proposed to operate a valve on a train directly by an armature utilizing the impact of the armature on the valve to cause the valve to open. Other arrangements proposed for operating a valve directly by an armature mechanically con trolled from the track have been so designed as to require considerable operating force or have been of a complicated type and so have been either inefiicient or expensive or both.

One of the features of the present invention by which other features hereinafter mentioned become commercially practicable concerns the provision of a receiving ar-v rangement which is both efficient and of simple construction. According to this feature OF CHICAGO, ILLINOIS, A CORPORA- TRAIN CONTROL SYSTEM 512,791, and in Great Britain March 17, 1930.

the armature of the magnet is provided with a blade of. very thin metal resting over a small slit or opening in a smooth surface, one side of the blade being subjected to atmospheric pressure and the other side being subjected to the pressure of the fluid used for controlling the brakes, the arrangement being such that normally the exit is closed dueto the pressure on the blade forcing it against the surface, the blade being adapted to slide over the surface under the control of the magnet and to connect the braking fluid to the atmosphere with a minimum amount of energy. With this design of re ceiving element the armature can be reliably operated by magnets on the track which are separated from the collecting plates by as great a distance as is required. In one form the receiving element can be provided with two pairs of collector plates, one pair acting as an operating pair and the other pair as a holding pair so that when flux flows between the holding pair, the operating pair cannot be effective as extensions for the armature are arranged to abut against pole pieces of the holding pair. In another construction, which is similar to the last in that it has two pairs of plates arranged at right angles to each other, it is possible to arrange for either pairto operate, that is to say, one pair can operate and the other pair can restore.

By means of the invention, it will be appreciated, that a very convenient, cheap and efiicient receiving element has been obtained which will enable the magnetic control from the track to be translated into pneumatic control on the locomotive without any electrical connections for intermediary purposes.

A further object .of the invention vide a train control system which is capable of being operated uniformly irrespective of whether the locomotive is going with the tender in front or the engine in front and in certain cases it may be desirable that the loco-- motive apparatus should also operate uniformly with respect to the track apparatus irrespective of the'direction in which the train is going, while in other cases it may be sufficient for it to operate only when the train is going in a normal direction providis to pro- 7 track and of two similar receiving elements j similarly disposed on opposite sides of the.

centre line of the locomotive so as to be operated upon by said track elements substantially simultaneously, the arrangement being such that when operated simultaneouslyno brake controlling or signal controlling operation would be initiated but when operated independently one "is operated and not the other, and then a signalling device or a. brake controlling element would be operated. i A

' A further feature of the invention applicable' to the second case above referred to isthat all the track elements are arranged to have their midpoints lying over the centre line of the track or under the centre line of the locomotive, while the receivingelements are arranged to lie over the centre line-of the locomotive; p A

" A further feature of the present invention applicable to both the cases above mentioncd is an arrangement whereby two distinct signals are'given on the locomotive of an audible character according to the condition of the brake apparatus, for instance, if a signal is clear an audible signal of a particular note or of a limited duration can be given while, when a sig'nal'is at danger an audible note of another frequency or a note of indefinite duration can be given. These and other features of the invention will be better understood by referring to the accompanying drawings in which:

Figures 1'8 illustrate the invention as applied to a system in which the track apparatuscontrols the locomotive apparatus in the same manner irrespective of the direction in which the train is travelling and irrespective of whether the locomotive" is running engine first or tender first, While Figures 9-11 illustrate the invention as applied to a system in which the track apparatus controls the locomotive apparatus for one direction of running in the same way irrespective of whether the locomotive is running engine first or tender first and exerts a restrictive action for the other direction of running.

Figure 1 indicates a section of track showing'track apparatus employed with'relation to distant and stop signals respectively.

''Figure 2 shows train controlling arrange-- ments carried by the locomotive.

Figure 3 shows the track apparatus illustratedin Figure 1 in greater detail.

Figurei shows the controlling arrange-' ments associated with the armatures of the of Figure r receivers X, Y, Z in Figure 2 and Figure 6. Figure 5 shows a section on the line Wm of Figure 4.

Figure 6 shows an arrangement which is alternative to that shown in Figure 2.

Figure 7 showsan enlarged view of part of Figure 6.

Figure 8 shows a section on the line g z ,Figure 9:;nd'cates a section of track showing a different arrangement of track apparatus employed with relation to distant and stop signals.

F igures'lO and 11 show the train controlling arrangements carried by the locomotive whichare employed in conjunction with the track apparatus shown in Figure 9.

A description will first of all'be given of the track apparatus and train carried a'p paratus shown in Figures 18.'

- Referring' to Figures 1 and 3' it" will "be noted that'the track apparatus associated with a distant signalcomprises two inductors A and B. The inductonAconsists.of a series of permanent magnets of cobalt steel arranged parallel to the rails of the track and symmetrically disposed, as regards the centre of the track, to the inductorB. Inductor B consists of an electromagnet having its poles lying in a. line parallel to the rails of the track and'arranged to be energized when the distaut signal is at clear. The arrangement is such, therefore, that if the distant signal is at clear then both the inductors A and Bare operative, whereas if the signal is at danger only the inductor A is operative. The electromagnet is contro'lled from a distantsignal lever in a circuit extending over contacts controlled by the semaphorezwm and the arrangements may be such that the electromagnet is also controlled from the track so that itscircuit is completed actually by the train itself so as to save'current consumption. Inductor C consists of a' number of "permanent.magnets 51 lying midway between the rails with'the magnets lying parallel to the track; At right angles to the mag nets 5-1 isan electromagnet 52 having itscore and exciting coil lying underneath the per manent magnets and having its polepieces 5% extending upwards so as to lie snbstan-- tially in the plane of the magnets 51. The coil of the electromagnetis connected in a circuit controlled in the manner described in connection with the eleetro-magnet at the distant signal, in acordance with the position of the stop-signal, that is to say it is excited when the stop signal is at clear and is not excited when the stop signal is danger.

On the locomotive thereare three receivers, the receiverXwhich is supportedmidwaybetween thewheels so as to be controlled by the inductor O andthe receivers'Y and Z which are arranged symmetrically. about the centre lineof the locomotive so as to be controlled- A when electromagnet the inductors B by the inductors B and A. It will be clear that whichever way the engine'is running, either tender first or engine first or whether it is: running-forward or in reverse, the re- 3 ceivcrs Y and-Z will be in such .aposition as to pass over the inductors l3 and A or vice versa,,while the receiver X will always pass over the inductor C. The receivers Y and are each provided with a pairof collecting plates ying in a longitudinal direction with respect to the track and having controlling armaturcs and 153 respectively, the arrangement being such that the collecting plates are effective to attract the. armatures whenever/the receivers Y and Z pass over an energized inductor such as Aer B. The receiver X is provided with two pairs of col lecting plates,.the. pair of collecting plates 6 and 7 being arranged longitudinally with respect to the track and the collecting plates land 5 beingarranged at right angles to the track. The armature 3 normally rests against the pole pieces of the collecting plates 4 and 5, the. arrangement.being such that 52is de-energized and the permanent magnets .51 of the inductor C are alone operative, then the collecting pla 6 and 7 when passing over the inductor C bccome energized and attract the armature 3. If, however, the electromagnet 52 is also en er ized then this causes flux to flow between the collecting plates l and 5 and so holdsthe armature in position irrespective of the pull oft-he collecting plates 6 and 7. consequent ly it will be appreciated that the electromagnet 52rcnders the influence of the permanent magnets 51 ineffective. Briefly, therefore, th e operation of the re celvers when a locomotive is passing-along the track in the direction shown by the arrow in Fig. 1 is as follows: lVhen the locomotive passes a distant signal similar to the signal D shown in Fig. 1, the receivers Y an d Z carried by the locomotive pass directly over 7 and A. respectively which are locatedon the track between the running rails and, according to the position of the signal, one or both of the receivers Y and Z will pick up flux from the inductors and operate their armatures. If the distant sig-. nal is at clear the inductor B will be eX- cited and both the receivers Y and Z *ill operate their armatures to cause a definite, characteristic.audible signal to be given on the locomotive which will be described later,

while if the signal is at danger the receiver which passes over the permanent magnet inductor A (i. e. Z in the case illustrated) alone operates its armature and a different characteristicsignal is given on the locomotive accompanied by a partial brake application.

The arrangement is such that if the receivers,

Y and Z are operated together one operation 1s produced, whereas if one is operated and not the other, irrespective ofwhich isoper;

ated and which is not operated, another result is produced in a manner to be described later. The object of this arrangement is-to ensure that, irrespective of the direction in which the train is running, the effect on the locomotive when passing a distant signal will always be the same'for the same conditions of trail r-c. lVhen the locomotive passes a stop signal, such as the signal S shown in Fig. 1,

the receiver X passes over a trackway inductor such as C which is located on the track in central position between the running rails. If this signal isat clear the coil in the traclrway inductor C is energized andall the collecting plates of the receiver X will pick up flux the result being, as previously described, that the armature of this receiver does not move. If, however, the stop signal S is at danger the coil of induct-or C is not energized with the result that only the collecting plates 6 and 7 pick upfiux and the armature is operated from the position shown in F ig..2 of the drawings so as to initiate an emergency application of the brakes, as will be described later.

It will be noticed in Fig. 2 that the'locomotive apparatus comprises two units, one the apparatus E for controlling a partial brake application which is in turn controlled by the receivers Y and Z and secondly the apparatus F which controls a complete brake application and is in turn controlled by the receiver X. By having two separate units it becomes possible with the apparatus described touse either the full train control system employing distant and stop signals with means for applying a partial brake ap-v plication at a distant signal and a complete brake application at a stop signal or to employ. a complete brake application at the stop signal only. That is to say if, for the purposes of economy or other reasons, it is desired to employ only the train stop signal instead of the complete system, the apparatus on the locomotive need only, consist of the train stop apparatus F and the receiver X, which apparatus is simple in construction and cheap to install. If atany time it is de sired to change from the simple train stop system to the full system employing distant and stop signals and having characteristic audible indications at distant signals it is only necessary to install the additional apparatus on the locomotive and on the track without disturbing the existing apparatus. It will be realized that the train stop apparatns F can readily be equipped with audible signalling devices as will be readily under stood by those versed in the art.

Before giving a complete description of the operation of the system, a description will be given of various constructional details. In the first place a description will be given of the arrangements controlled. by and for controlling the armatures of thefreceivers iio its

. ture and normally rests over a longitudinal v the strip against the upper opening of the X, Y and Z. For this purpose reference will be had to Figs; 4 and 5 which, while they illustrate more particularly the armature of receiver X, apply except for one or two minor 5 constructional alterations also to the receivslit 92 opening to a port 58 which is normally connected to the vacuum reservoir of the train. The suction from the vacuum reservoir through the slit 92 is sufficient to hold slit 92 and so form an air-tight joint. The phosphor bronze strip 63, it will be noted, serves as a slide valve and, when the armature is operated so that it contacts with the pole pieces 59 and 62 the slit 92 is uncovered and the port 58 is connected to the atmosphere. The resetting of the armature is effected by a plunger 8 operating in a chamber 71; the operation of the plunger 8 is effected by connecting the port 57 .to vacuum so that the plunger 8 is sucked inwards, thereby acting on the extension of the armature and restoring the armature so that it rests against the pole pieces 60 and 61. It must be appreciated that by means of the constructlon shown a very simple electromagnetically op-.

erated slide valve for use in connection with vacuum brake controlling gear has been evolved. V

The train stop apparatus F consists of a diaphragm 11 which forms one of the walls of a chamber 12, which is connected by means of the pipe 46 to the slide valve controlled by the armature 3. The diaphragm 11 is subjected on one side to pressure from the spring 10 which serves to prevent it from collapsing when the chamber 12 is evacuated, this evacuation taking place through a constricted orifice 13 connected to the pipe 42 whichin turn is connected to the vacuum reservoir of the train. The normal condition, therefore, is that there is a vacuum in the chamber 12 and the diaphragm 11 is prevented from collapsing by means of the spring 10. The slide valve 53 connected to the centre of the diaphragm remains in the position shown, closing the pipe 74 leading from the train pipe 43. If now, due to the armature 3 operating, the vacuum in the chamber 12 disappears, then the spring 10 forces the diaphragml1 outwards and the slide valve 53 opens the pipe 74 and so causes a full brake application. The acknowledging plunger 37, which would preferably be located in a position normally inaccessible to the engineman', that is to'say,

in a position such that he has to leave the cab in order to operate it, controls a slide valve arrangement adapted to perform a dual function, that is to say, at the port 55 it connects the pipe 42 and the vacuum reservoir to the pipe 45 to effect the operation of the resetting plunger 8' so as to restore the armature 3 of the receiver X, while at the port 14 it connects the pipe 49 to atmosphere and thereby the train pipe 43 and so ensures that the engineman cannot maintain the plunger 37 depressed. I

The arrangement for giving the two different audible indications on passing a distant signal as well as the arrangements for controlling the partial brake application are indicated in Fig. 2 by the reference E and for convenience will be termed distant control apparatus seeing that it only becomes operative at a distant signal. This apparatus comprises a slide valve 21 which normally covers the end of a pipe 94 which is of substantially smallerdiameter than the pipe 74. The slide valve 21 is controlled by two diaphragms 23 and 22 so as to normally take up the position shown as the neutral position. These diaphragms 22 and 23 each constitute one of the walls of the chambers 24 and 25 respectively. The other walls of the chambers 24 and 25 also consist of diaphragms 30 and 29 respectively and the chambers 24 and 25 are similar in every respect. The diaphragm 29 controls the slide valve 32', while the diaphragm 30 controls the slide valve. 31. Each of the chambers 24 and 25 is connected to the vacuum reservoir of the train through the restricted orifices 27 and 26 and the pipes 40 and 39 respectively. Springs 34 and 33 are provided in the cham-' bers 24 and 25 for the purpose of preventing diaphragms 30 and 29 from collapsing. The diaphragms 22 and 23 remain in the position shown because they are rigidly connected together and the suction on'the right-hand side of the diaphragm 22 is balanced by the suction on the left-hand side of the diaphragm 23. Consequently the normal position is as shown in the drawings. The chamber 24 is connected by the pipe 47 to a valve 18 controlled by the armature 16 in the same way as has been described with relation to the valve controlled by armature 3. Similarly the chamber 25 is connected by the pipe 44 to the valve 17 controlled by the armature 15.

The arrangement is consequently such that if the armatures Y and Z are both operated then the vacuums in chambers 24 and 25 will be dissipated, with the result that the pressure on the left-hand side of the diaphragm 23 and the pressure on the right-hand side of the diaphragm 22 continue to balance each other. On the other hand the springs 34 and 33 will become effective to operate the slide valves 31 and 32 and thereby permit the entrance of air through the whistle 35 and the pipes 56 and 56m past the slide valves 31 and 32 through the passages 95 and 96 to the pipe 94 and the train; pipe 43. Only a limited amount of air can get through the. whistle which, however, will be sufficient to operate the reed in the whistle and to give a low pitched note while at the same time it allows air to pass to the train pipe 43. Such admission of air will be insuificient to 'afl'ect the brakes. V 1

If, on the other hand, one only oi. the receivers Y or.Z is, operated, and it should be noted that it does not matter which, then the pressure on the opposite sides ofthe diaphragms 22' and 28 respectively will become unbalanced and the slidevalve 21 willbe moved .either to the right or to the left, in either of which positions it will open the pipe 94 and allow air to enter through the siren 28, thus giving a signal of high pitched note quite distinctive from that produced by the reed of the whistle 35 and at the same-time admitting air to the train pipe 43 to such a degreeas; to cause a partial brake application. It should be'mentioned that either one or the other of the slide valves 31 or 32 will also be operated causing the whistleto operate but this will generallybe almost imperceptible in view, of the loud noise produced by the-siren 28. Theengineman by operating the plunger 36 quickly. can effect the restoration of both the armatures 15 and 16 in the case where both the receivers Y and X have been operated, or either of the armatures 15 and 16 in the case where only one of-the receivers has been operated by bringing. the port 54 toconnect the pipe 41 with the'pipe 48-, the pipe 41 beingconnected to the vacuum reservoir on thetrain-JAt the same time as the plunger'36 is operated the pipe 96 is connected through the branch pipe 50 to theatmosphere at port 38,-thus ensuring that the brakes will be partially applied if the driver does not restore his acknowledging plunger quickly. The closing of the valves l? and/or 18 allows the chambers 24 and/or 25 to be evacuated through the restricted orifices 27 and/or 26 respectively. In this way the diaphragms and the slide valves will be gradually brought to the posi tions shown in the drawings when the train becomes again under the control of the driver. A description of the operation of the train control system according to the invention" Wlll nowbe given. In the first place it Wl-ll be assumcdthat an engine isapproaching the distant signal D from the left of Fig.1 and that the distant signal isat clear. 't will also be assumedthatthe. locomotive is run-, ning withthe engine in front, as shown in Fig. 2, with the receiver Y on the left of the track and; the receiver Z onthe right of the track.v lnthese circumstances the electromagnet Bwillbe energized and consequently asthetrain passes. over the inductorsxB and A respectively the collecting plates of the re' ceiversY and Z will be afiected by the mag.- netic field of the inductors B and A so that fiuX flows across the collecting plates and the armatu'res l5 and 16 are attracted. The efiect of this is that the pipes 44 and 47 are sub stantiallysimultaneously connected to atmosphere with the result that the pressure in the chambers 24 and-25 rises to that ofthe atmosphere. Consequently thepressures on the right-hand side of the diaphragm 22 and the lett-handside of the diaphragm 23 remain balanced and the slide valve 21 maintains the pipe 94 closed. The di'aphragms 29 and 30 are, however, moved to the right and left respectively operating the slide. valves 32 and S1 and soconnecting the pipes 935 and.96 to the pipes 56a-nd 56a, thereby causing air to be sucked, in pasthe reed ofthe whistle 35. In this way a characteristicaudiblelsignal is given to the engine driver indicating to him that he is passing a clear signal so that even if it is foggy andhe cannot see the sig-f nal-himselthe will know that the track 'is clear. The engine :driver then presses the acknowledging plunger 36 and efiects the restoration of the arinatures 15 and 16 by means of the resetting plungers 20 and 19 respece tivelyp- He immediately, however restores the plunger as, if not, he would affect the application of the'brakes through theport 38. The train then proceeds along the-track until he reaches the stop signal S. f

As the distant signal is atclear it"follows that the stop signal itself is also at clear. The electromagnet of the inductor C is therefore energized and consequently the inductor G acts on the receiverX' both to send polarizing flux between the collecting plates 4 and 5 as-well as between the collect in g plates 6 and 7. As the armature normally rests so as to connect the collecting plates 4 and 5 it will be clear thata very small holding flux between the collecting plates 4 and 5 will be suflicient to withstand a much greater polarizing fluxcreated across the collecting plates 6 and 7 Consequently inthese circumstances there will'beno operation of the armature 3 and thetraincanproceed with out any interruption or notification. It may happen that there is associated with the stop signal" a second signal constituting the distant signal for a. second stop signal; In. these circumstances the inductors A, B and. G will be arranged side by side and, assuming again that the 'second stop signal is at clear, then the, inductors B and A will operate on the receiversY and Z in the manner already described to cause a toot on the whistle 35 v and the engine driver will be'reqn-iredto op-- crate the plunger 36. 1 It; will now be assumed that a train isapproaching the distant signal D withthelocomotive having its engine in front. and that the distant signal D is at .danger, in which case the electromagnet B will not be energized. In this case when the receiver Z passes over inductor A flux will pass between the collecting plates to cause attraction of the armature 16 and the connection of the pipe 47- to the atmosphere. The receiver Y, however, will be unaffected as there will be no magnetism generated from theinductor B. In this case, therefore, only the chamber 24 will be connected to atmosphere and consequently the pressure on the diaphragm 23 will be sufficient to cause the'slide valve 21 to open the pipe 94 while at the same time the diaphragm 30 will move to operate the slide valve 31 and open the pipe 95. The sucking of air through the whistle 35 willcause the whistle to sound but at the same time air is sucked with much greater power through the siren 28 causing the siren to produce a high pitched note quite distinct and much more powerful than that produced by the whistle 35. The engineman even in-fog,therefore, knows that he is passing a distant signal at danger and can at once operate the plunger 36. This plunger at once restores the armature 16 by means of-the resetting plunger 19 while connecting the pipes and 9 6 to atmosphere at port 38 and is then restored. The closure of the valve 18 cuts off the pipe 47 from atmosphere and enables the air in chamber 24 to be gradually exhausted so that the slide valves 21 and 31 are restored to the position shown in the drawing. This ensures a partial brake application, and also that the engineman is made aware of what is happening and, only by taking the necessary steps can he assume control of the train when the distant signal shows -dange-r.' I

If it should be that'the engineman passes the distant signal at danger and proceeds far enough to pass the stop signal S which is also at danger, then the electromagnet of the inductor C will be de-energized and the permanent magnets will be effective to cause flux to pass between the collecting plates 6 and 7 and so attract the armature 3. Armature 3 by openin the-valve 9 to atmosphere will cause the diaphragm 11 to move to the left and so operate theslide valve 53 and connect the pipe 74 to atmosphere. This will cause a full application of the brakes and such application can only be removed by the engine driver operating the plunger 37. If, as appears desirable. the plunger 37 is only located in a position which is normally inaccessible to the engineman. (i. e. in a position which he can onlv reach from the ground) then only after the engine had come to rest can the plunger 37 be operated to effect the operation of the resetting piston 8 and the restoration of the armature .3. i It may happen in the case referred to. above where the distant signal of a second stopsignal is fixed on the same post on the stop signalS. that the second distant and stop sig nals are atdanger but that the signal S has become clear. In such a condition it will be possible for the engineman to proceed but only after the siren 28 has been sounded and a partial brake application made in the manner already described for the distant sig nalDat danger.

The operation has been described in connection with the train inoving from left to right with the engine of the locomotive in front. If the tender of the locomotive were in front'then the receiver Z would pass over the inductor B and the receiver Y over the inductor A and in such circumstances if the signal were at clear, both receiversY and Z would be operated-as before andthe effect would be exactly the same. If, however, the distant signal were at danger, thenthe re ceiver Y would be alone operated and this would have the effect of connecting atmosphere to the chamber 25, in which case the diaphragm 22 and slide valve 21 would move to the left and uncover the pipe 94'so as to sound the siren and to'efiecta partial application of the brakes. Similarly the slide valve 32 wound would open to cause the whistle to sound but this 'whistle would be almost inaudible in these circumstances in comparison with the sound'o'f the siren 58.

' An important feature of the element E is that,'irrespective of whether the receiver. Y or the receiver Z is operated alone, the same result will be produced. I

The case will now be considered of where it is desirable to reverse the engine for some reason or other; that is to say, it is moving backwards from right to left along the track instead of from left to right with the engine of the locomotive in front. In this case exactly the same effect will be produced as that described when the engine is moving forwards, as it will be appreciated that the op eration of the receivers is the same irrespective of the direction of approach. The fourth possible condition is where the engine is moving backwards from right to left with the tender in front and this case will be ex actly the same as that described where the T engine is moving forward with the tender in front. As regards the relationship of the inductor C and the receiver X, it will be noted that the operation is the same irrespective of whether the engine is moving forward or backward with the engine of the locomotive in front or the tender in front. This arrangement, therefore, saves any necessity for providing means for reversingthe control and the whole of the automatic train controlling arrangements can be made substantially independent of the main controlling arrangements.

An alternative arrangement will be described with reference to Figs. 6, 7 and 8. The arrangement shown in Figs. 6, 7 and 8 is a modification of that shown in Fig. 2, more particularly as regards the construction of the distant control apparatus E and the stop signal control apparatus F. There are other slight minor changes which will first be dealt, with. In the first place the whistle 35 is con nected: to pipes 73 and 72 leading to sealed casing 76. and 77 enclosing the receivers. Y and 2 respectively. The receiver X is also surrounded by a sealed casing 98 which; has, however, a special opening, located su'fiiciently" highfromtl-ie track to ensure that it will not be clogged or blocked by dirt or the like from the vicinity of the track or from undernea-th the engine. The enclosure of the receivers in, the chambers has the further advantage thatthere is no danger of pieces of material or the like being sucked into any of the openings in the slide valves such as 17, 18 or 9 and filling the slide valves. It will be appreciated that thereceivers X, Y and Z are located beneath the locomotive and consequently some protection of this kind is advisable. It should also be mentioned that the collectingplates of the three receivers are so: designed that. they as far as possible completely'fill' the space inside the casings, so as to leave as little air space as possible.

The modified distant control apparatus E shown in Figure 6 and in greater detail in Figures 7 and 8. comprises a cylindricalhousing H which two pistons 78 and 7,9 opcrate, one in each end of the housing. Between the pistons and loosely secured between two flanges on a shaft joining them is a floating valve ring70. which is normally pressed by atmospheric pressure'against an opening 90 connected to the train pipe 43 which is in turn connected to the vacuum reservoir of the train. The floating valve ring is free to move at right angles to the shaft so as to enable the air pressure to. maintain the ring 70 seated against the substantially rectangular shaped slot forming the opening 90 as shown in Figure 8 and ensures that there is no leakage of air to the trainpipe 43 through the siren 28. Rubber rolling rings 85 and 86 are provided in recesses between the pistons 79 and 78 and the inner cylindrical face: of the housing H. These rollingrings are free to roll as the pistons are moved in the cylinder while at the same time ensuring that there is no leakage of air to the chambers 67 and 68' through the siren 28.

The siren 28 is mou-nted in a circular opening on the upper side of the housing Hv just over the floating ring 70. Each of the pistons is normally engaged by afloating collar such as the collar 100 it beingund'erstood that the arrangement of the'two ends of the housing H are similar. The floating collars are acted upon by the springs 87 and 88 which in: turn act on the pistons 78 and 79 to hold them in the position shown with the floating ring 'ZO-covering the opening 90. The floating collar 100 slides on a rod 89 secured to the end of the housing and having a flange which pre' vents the spring 88 from acting'on the piston 7 9; when the piston is moved to the left of the position shown. The'spring 87in asimilar manner isprevented from acting on the piston 78 when the piston 78 is moved to the right of. that shown. his arrangement ensures the accuratepositioning of the floating ring '70 overthe opening 90' and'prevents the position-of the ring being dependent upon the relative strengths of the springs 87 and88.

The chambers 68 and 67 betweenthe ends. of the housing H and the pistons 78 and 79 respectively are normally exhausted, being connected to the vacuum reservoir of the train through the restricted openings 83 and 84,

while ports 44a and 47a are connected to'pipe's 44 and 47 adapted to be connected to the atmosphere in. a manner to be described later. If both these chambers are connected to the atmosphere simultaneously through the ports 44a and 47a -the state of equilibrium will not be destroyed and the pistons and slide valve will remain in the position shown. If, however, only one of these chambers, and it does notmatter which is connectedsto the atmosphere, the atmospheric pressure willbe suflicient to move the connected pistons either to the right or to the left according to which of the chambers'is connected to: the atmos-. phere and the valve ring 70 will openthe port and connect the train pipe 43'to atmosphere.

V A description of the manner of operation of the apparatus shown in Fig. 6 will now be given. It will be assumed: that an engine is approa'chingthe distant signal D from the left of Fig. 1 and that the locomotive isrun-, ning with the engine in front with the receiv'er Y on the left of the track and the ro ceiver Z on the right of the track. It will not be necessary in connection with Fig. 6 to consider the circumstances when the locomotive is travelling tender first and. in reverse as it will. be realized that the system about to be described is as regards universality-of operation similar to the system'described in connection with Fig. 2. 7 If the distant signal is at clear the electromagnet B associated with the signal is energized and consequently as the train passes over the inductors plates of the receivers Y and Z will'be affected by the'magnetic fields of these inductors so: that flux flows across'the collecting B and A the collecting will be no operation of the armature and the traincan proceed Without interruption.

Itwill now be assumed that the train is approaching the distant signal D and that this signal is at danger. In this case, the inductor B will be dead and thereceiver Z which passes over the inductorA will alone pick-up flux thereby causing the attract-ion of the armature'16. The chamber 68'will now be connected to atmosphere through pipe 47, slidevalve 18, sealed casing 77, pipe/('2 and whistle 35 while the chamber 67-will remain evacuated. This means that the normal state of equilibrium in the distant control apparatus Eis destroyed and the valve ring 70 will move to the right and connect the train pipe 43 to atmosphere through the siren 28, thus causing a partial brake application to be made and the siren operated. As the receivers practically fill the sealed casings there will be very little air space in the casing 77 and, therefore, the time taken for the pressure in casing 77 to fall to a low enough value to allow the operation of the slide valve will be negligible. The whistle 35 will also operate at this time but as already mentioned, the noise made by the siren willpractically drown the noise made by the whistle. The siren will produce a high pitched note quite distinct from that produced by the whistle and indicate to the driver that the distant signal which he has passed is at danger. He will at once operate the acknowledging plunger APE and thereby restore the armature 16 by means of the resetting plunger 19 and as he at the same time connects the train pipe 43 to atmosphere at port 38, he must immediately restore the plunger. On the restoration of the armature 16 the slide valve 18 will he closed and vacuum will be restored in the chamber 68 through the restricted orifice and pipe 69 due to the fact that air is now cut off from the chamber 78. The state of equilibrium will gradually be restored, the valve ring 70 restoring to its normal position andreleasing the partial brake application and at the same time stopping the operation of the siren. It will be understood that the whistle 35 will also stop when the slide valve 181is closed.

If it should happen that the engineman passes the stop signal, which follows the distant signal andwhich is also at danger,

then the electroniagnet' of the inductor C will he de-energized and the collecting plates 6 and 7 will be influenced by the permanent magnets and flux will pass between these collecting plates and cause the armature 3 to be attracted. The diaphragm 11 of the train stop apparatus F is normally held in the posi'-* tion shown by atmospheric pressure, air being admitted through the orifices 6t-and to the left-hand side of the diaphragm, while vacuum is maintained through a restricted orifice on the right-handside of"-the diaphragm. \Vhen the slide valve 9 opens, owing to the operation of the armature 3, atmospheric pressure is built up on the right-hand side of the diaphragm 11 as this side of the diaphragm will now'be connected toatmos phere through pipe 46, slide valve 9, sealed casing 98 and the inlet 93. I The diaphragm will therefore move to the left carrying with it the valve 66 which thereupon opens-and connects'the train pipe 4-3 to atmosphere through theorifices 64 and 65 which are of a suitable size to allow an emergency brake application to be made. An emergency brake application will thus be made which can 'only be released when the engine driver presses his acknowledging plunger APF; If thisis done, preferably only'after the train has come to rest, the vacuum chamber V will be connected to the resetting piston 8 through the pipe 80, port 82 and pipe 45 and this pis ton will operate and restore the armature 3. The. driver must, however, immediately re store the plunger APF, as, if-not, the train pipe 43 will be connected to' atmosphere, through the port 14 and it will not'be possible to completely release the brakes. When the armature 3. returns to its normal position vacuum gradually restores in the chamber to the right of diaphragm 11 and the diaphragm.

will move to the right and close the valve 66. When the valve 66 is closed, the train again becomes under the control of the driver and he can proceed to the new signal.

As has been mentioned in connection with the arrangement shown in Fig.2, it may be desirable to fit only one of the brake 'con trolling arrangements'E' and]? and not the two together. In the apparatus shown in Fig. .7, ispossible to remove the distant control apparatus E by unscrewing it and thereafter fitting a. plug in the threaded portion of the train pipe connection extending tothe slit 90. i

It willbe appreciated that this arrangement is capable of progressive application in that a full train stop system without sige nalling devices could be provided'in the first place and that distant signal control with different audible s gnals could he added at any time without involving any radical change in the part already fitted. i

A description will now be given of the track apparatus and locomotive carried ap paratus shown in Figs. 911. In these figures, Fig. 9 shows the track apparatus, while the remaining figures show the locomotive controlling apparatus which works in conjunction therewith, Fig. 10 showing the control valve and audible signalling devices and Fig. 11 showing the receiver relay and the acknowledging plunger.

Referring now to Fig. 9 the track apparatus located at a distant signal comprises A and B inductors similar to those shown in Fig. 3 but arranged in a different manner on the track. The B inductor which consists of an electremagnet is located on the track with its core at right angles thereto, while the A inductor which cons sts of a set ofpermanent magnets of cobalt steel is located lengthwise along the track to the rear of the B inductor. The distance between the A and B inductors can conveniently be somewhere about 10 feet but can vary between very wide limits. The B inductor is controlled from a distant signal lever in a circuit extending over contacts controlled by the semaphore arms and the arrangements may be such that the B inductor is also controlled from the track so that its circuit is completed actually by the train itself so as to save current consumption. The C inductor which is located at a stop signal consists of an electromagnet and a permanent magnet arranged as shown with the electromagnet lying over the centre of the permanent magnet and is identical with the C inductor shown in Fig. 3 and is controlled in a similar manner.

The receiver relay shown in Fig. 10 which is mounted on the locomotive at a suitable height, for instance, four inches above the rails, consists of four collecting plates 120 121,122 and 123. ed centrally in thereceiver and is arranged to be operated by the flux collected either in plates 120 and 121 or in plates 122 and 123. A thin stainless steel plate or phosphor bronze strip 125 and a slot 126 constitute a slide valve of the type which has already been described in detail. with reference to Figs. 4c and 5. The normal position of the armature 124 is in contact with the pole pieces 12'? and 128 and with its other extremities remote from the pole pieces 129 and 130.

WVhen magnetic flux is collected by the plates 120 and 121- due to the receiver passing over the A inductor or the permanent magnet of the C inductor (electromagnet unenergized), the armature is attracted to the pole pieces 120 and 130 and the slide valve 125 uncovers the slot 126. The armature can be restored to its original position either by the receiver passing over a B inductor in an energized condition whereupon the magnetic flux collected therefrom by the plates 122 and 123 will cause the armature to be restored or by the manual operation of an acknowledg- An armature 124 is mount-v ing plunger 113. This latter operation will be described in detail later. 7

A description will now be given of the valve structure shown in 'Fig. 10. This valve structure comprises a housing 101 which is mounted directly on the drip trap 108 which forms an extension of the train pipe 132 and carries at its lower end an auxiliary housing 102 which supports a stretched rubber diaphragm 103. This diaphragm in turn supports the sliding member 104 of a lift valve which carries at its upper end the padded valve washer 105, this washer being arranged to engage with the circular ridge 106 of the housing 101 when the valve is seated. The chamber 107 above the washer 105 is connected directly to the drip trap 108- and hence to the train pipe through an extended orifice while the chamber 109 below the rubber diaphragm 103 is connected to the vacuum reservoir of the train via the pipe 110 and the restricted orifice 111. A

chamber 112 below the washer 105 connects.

with the pipe leading to the audible signals in the cab of the locomotive, while a shutoff valve 133 is provided above the washer which can be screwed down if so desired, so that it engages the sliding member and prevents its operation. This will be employed if it is desired to eliminate at any time the automatic control. y

The valve structure is located underneath the locomotive in close proximity to the train pipe and is connected to the receiver relay by the pipe 110 which can conveniently be of short length so that the valve structure and relay can be located in the same place underneath the locomotive It is then only necessary to have two pipes extending upwards into the locomotive cab, one connecting with the signalling device and the other connecting with the acknowledging plunger shown in Fig. 11.

This acknowledging plunger consists of a push button 113 which is held in its unoperated position by a coiled spring 137. The chamber below the push button is connected by apipe .114 to a chamber 115 which is covered at its lower end by a rubber membrane 138. When the plunger is operated abruptly the air in the pipe and in the chamber below the push button and the chamber 115 is compressed and the rubber membrane 138 will therefore be forced outwards and if the armature 124 is operated the membrane will engage the plate 116 and restore the armature to the position shown. A leak hole 117 is provided button so that if the driver endeavors to hold the push haust out through this leak hole and the rubber membrane will restore. It is therefore impossible for the driver to eliminate the automatic control by maintaining the plunger depressed. It will be understood in the chamber below the push button depressed air will ex- 1 that if desired a piston which is restored by:

a coiled spring can be substitutedfor the rubber membrane.

A description will now be given of the manner of operation of the system when the collecting plates 120 and 121 of the receiver will pick up flux from a permanent magnet located lengthwise along the track; The armature 124: will therefore be operated and the slide valve 125 will be operated to uncover the slot 126. Vacuum will therefore be destroyed rapidly in the pipe 110 and chamber 109 and the sliding member will be moved upwards under the influence of the rubber diaphragm 103 to unseat the valve. This movement of the slide valve will be accelerated due to the fact that as soon as the washer commences to move air will be sucked out from the chamber 112 past the circular ridge 106 into the train pipe. The train pipe will now be connected directly to the horn 134 and this will commence to sound. The receiver relay, however, will almost immediately encounter an energized electromagnet which is situated at right angles to the track and therefore the collector plates 122 and 123 will pick up flux and restore the armature 124 to its original position. The slot 126 will therefore be closed, vacuum will build up gradually in the pipe 110 and chamber 109. and-the diaphragm 103 and the lift valve will restore. The restoration of the lift valve is, however, further delayed due to the fact that there will he a somewhat reduced pressure in the chamher 112 owing to the exhaust of air to the train pipe. It will be realized therefore that the sliding member 104 will be operated rapidly and restored comparativelyslowly so that even if the permanent magnet and electromagnet are located quite close to each other along the track the horn 134 will be sounded for a convenient length of time, for instance, one second.

When the locomotive passes; a distant signal at danger the electromagnet will not beenergized and'therefore the slide valve will not be restored automatically. The horn will therefore continue to sound and indicate to the driver that he is passing a signal at danger. If he is alert he Wlll operate his acknowledging plunger in the manner already described, so that the rubber membrane will be extended and will restore the armature 124: to the position shown to close,

the slot 126.' Vacuum will therefore be once more built up in the pip-e 110 and the chamher 109 and the sliding member will restore to'the position shown. I

At a stopsignal the electromagnet is located over the permanent magnet and therefore if the electromagnet is energized as it operated. If,-however, the stop signal is at danger the permanent magnet will alone be operative and as the receiver does not pass over any further magnets on the track the slide valve will be operated and not restored automatically. The horn will therefore continue to sound to indicate to the driver that he is passing a signal'at danger. Acknowl edgment must therefore be made in the manner described.

It will be realized, therefore, that two audible signals are given to the driver, the short blast on the horn indicating that the signal is at clear, while an extended blast indicates that the signal is at danger. If it is desired to provide two signals having different notes, a siren 136 can be mounted in the pipe leading to the horn 13 in the position shown. This siren is provided with a heavy spinning member so that a certain amount of time will elapse before it gets up sufficient momentum to start emitting its note. A suitable delay period Would be about two seconds. With this particular arrangement of two audible signalling devices, at clear distant signals only the horn will be sounded as the pipe leading to the horn and siren is only connected to the train pipe for about one second, while at stop or distant signals at danger this pipe will be connected to the train pipe for an appreciable length of time and it will therefore be possible for the spinning member of the siren to get up sufficient momentum to cause the siren to emit its note. The sound emitted by the siren will be imposed upon the sound emitted by the horn and this sound will be quite distinct from the note emitted by the horn alone, furthermore this combined sound will be emitted for an extended length of time while the note emitted by the horn alone will only be of short duration.

It will be appreciatedthat a train control and cab signalling system has been evolved which is very simple in construction particu larly due to the fact that no duplication or reversal of parts is necessary and is eflicient in operation in that it enables an audible signal to be given every time a distant signal is passed.

The invention further has the advantage It will be understood that the invention can be considerably modified without departing from the spirit of the invention. For instance in country districts it may be disadvantageous to employ electromagnets and under such circumstances mechanically operated permanent magnets may be used instead of the B and C elements already described. The permanent magnets will be mounted so as to rotate through an angle of 90 about a central pivot and their normal position will be parallel to the track, being maintained in this position by a suitable coiled spring against a permanent stop. Detection contacts will also be provided so that the existing signal arm repeater circuit will detect the normal or stop position of the magnets while the rotation will be efiected by means of an extension of the existing mechanical pull off wire. At a distant signal when the signal is at clear the permanent magnet replacing the B electromagnet willbe set at right angles to the track so that it will reset the receiver in exactly the same way as a B electromagnet.

At stop signals at clear the permanent magnet will be at right angles to the track and will have the same effect as a C inductor with its electromagnet energized as it will merely hold the receiver armature in its nor-' mal position. I

By employing a purely mechanical arrangement of this kind a considerable saving in batteries may be elfected.

I claim:

1. An arrangement for magnetically controlling the operation of a brake control or signalling element on a locomotive in which an armature in a magnetic circuit which is V influenced by magnets on the track is arranged to effect the connection of the train pipe with the atmosphere by moving a blade of thin metal from over a slit or opening in a smooth surface against which the blade is normally pressed by the diflerence of fluid pressure on its two sides.

2. Apparatus for use on a locomotive in a train control and/or cab signalling system comprising two pairs of collecting plates, each pair being adapted to be excited by magnets located along the track, in which an armature operating between the pole pieces of the two pairs of collecting plates is adapted to rest normally against the pole pieces of one pair and to be operated to the pole pieces of the other pair when the said other pair is alone excited so that if both pairs of collecting plates are operated simultaneously then the first pair of collecting plates will be effective in preventing the armature from operating under the force exerted by the other aair.

I 3. An arrangement for use on a locomotive in a train control and/0r cab signalling system in which an armature operates between the pole pieces of two pairs of collecting plates and is adapted to be moved from either pair of pole pieces to the other by the excitation of the appropriate pair of collecting plates and a valve opened by the armature as it moves in one direction and closed by the armature when it moves in the reverse direction. 7

4. An arrangement as claimed inclaiin 3, comprising a pair of collecting plates arranged on opposite sides of the pivot about which the armature turns and a blade of thin sheet metal connected to the armature and adapted to be moved over a smooth surface containing a slit or opening for connecting the train pipe to the atmosphere.

5; Track apparatus for use in a train control and /or cab signalling system comprising two track elements arranged so as to have their pole pieces equally spaced from each other with their mid points lying over each other on the centre of the track characterized in that one of said elements is adapted to be always operative while the other of said elements is adapted to be rendered effective or non-effective in accordance with track conditions.

6. Apparatus for use on a locomotive in a train control and/or cab signalling system comprising two pairs of receiving elements each pair being adapted to receive magnetic impulses transmitted from the trackway and being arranged so that the mid points or" each pair lie in the vertical central plane of the locomotive characterized in'that one pair of receiving elements when operated independently of the other is adapted to cause a brake controlling and/or signalling element to operate while the other pair of receiving elements if operated substantially simultaneously with the first pair is adapted to prevent such operation being brought about.

7. A train control and/or cab signalling system in which the application of the brakes and/or the operation'of the signals is controlled by magnets located on the track, characterized in that two magnets separated from and at right angles to each other'are located in the vicinity of the distant signal and two magnets superimposed over each other at right-angles are located in the vicinity of the home signals for the purpose of controlling a single'receiving element on the locomotive in different ways.

8. A train control and/or cab signalling system in which the application of the brakes and/or the operation of the signals is controlled by magnets located on the track, characterized in that the magnets located in the vicinity'of a distant signal are adapted to operate the single armature of the receiving element andsubsequently to restore it if the signal is at clear while magnets located in the vicinity ofthe home signal are arranged to operate said armature only if the home signal is at danger.

9'. In a train control and/or cab signalling system in which the operation of a pneumatically operable audible signalling device is adapted to be initiated and stopped by track apparatus to give a sound of limited duration to indicate one condition of the track, the provision of a second audible signal subsequently operated, but not stopped by track apparatus so as to give a sound terminable only by apparatus on a locomotive for the purpose of indicating a difierent condition of the track. 7

10. Apparatus for use on a locomotive as claimed in claim 9 in which the further audible signalling device comprises a siren provided with a heavy spinning member and adapted to become audible only after a predetermined time, which siren is connected to the same pipe or its equivalent as the first audible signalling device.-

11. Track apparatus for use on a locomotive in a train control and/or cab signalling system as claimed in claim 5 comprising a magnet which is adapted to be rotated about its centre so as to take up a position either parallel or at right angles to the track in accordance with the conditonof the track.

12. Track apparatus for use in a train control and/or cab signalling system as claimed in claim 5 in which one track element lies along the centre of the track while the other track element lies at right angles to the track.-

13. Apparatus for use on a locomotive in a train control and/or cab signalling system comprising a pair of similar receiving elements arranged at equal distances from but on opposite sides of the centre line of the locomotive characterized in that each receiv ing element when operated independently of the other is adapted to cause a signalling device and/or a brake controllingelement to operate while the two receiving elements are so arranged that if they are both operated simultaneously or substantially simultaneously no such operation is brought about in which each receiving element comprises'a pair of magnetic collecting plates having pole pieces adapted to operate on a common armature.

14. A train control and/or cab audible signalling devices comprising a whistle and a siren are provided the siren being 15. Apparatus for use on a locomotive in a train control and/or cab signalling-system as claimed in claim 6, in which the recelver velement or elements are housed in sealed cas- 7 ing and operate to connect an exhaust chamber or pipe to atmosphere in the casing.

16. A train control and/or cab signalling system in which two track elements-are arranged at equal distances from but on opposignalling system as claimed in claim 8 1n which two' site sides of the center line of the track and in which a pair of similar receiving elements are disposed at similar distances from but on opposite sides of the center line of thelocomotive so as to be operated upon by said track elements substantially simultaneously characterized in thateach receiving element when operated by one of said elements independently of the other is adapted to cause a signalling device and/or a brake controllingelement to operate while the two receiving elements are so arranged that if they are both operated simultaneously or substantially simultaneously no such operation will be brought; about, and asecond signalling device operatedconsequent to the operation of either or both of the receiving elements.= I; v

17 A train control and/or cab signalling system in which two track elements are arranged at equal distances from but on opposite sides of the center line of the track and in which a pair of similar receiving elements are disposed at similar distances from but on opposite sides of the center line of the locomotive so as to be operated upon by said track elements substantially simultaneously characterized in that each receiving element when operated by one of said elements independenly of the other is adapted to cause a signalling. device and/ or a brake controlling element tooperate while the two receiving elements are so arranged that if they are both operated simultaneously or substantially simultan'eou'sly no such operation will be brought about, a second signalling device operated consequent to theoperation of either or bothvof the receiving elements, and a vehicle-car'ried acknowledging device operable by the engineman to retire said signalling devices.

118. In a train controlsystem applied to a pneumatic braking system, vehicle equipment comprising a combined signalling and brake control valve normally maintained inoperative by a differential in pressure, a receiver armature operative by an influence transmitted to it by magnetic induction from the trackwaylto destroy the normal differential to bring about the actuation of said valve, trackway'means effective under clear traffic conditions in advance to promptly restore said receiver armature, and a chamber in said valve efi-ective to introduce a lag in its restorationto insure its remaining operated for a sufiicient time period to perform its signalling function eventhough prompt restoration of said recever armature occurs.

- In testimony whereofI aiiix my signature.

ALFRED ERNEST HUDD. 

